Wind energy has been used for many years to generate electricity. Windmills and turbines have been utilized to capture wind to convert the wind energy to electricity through the use of a generator. Generally, a plurality of blades is used to best harness the wind to rotate a shaft. A generator, connected either directly to the rotating shaft, or indirectly via a series of rotating and connected shafts, is used to convert the wind energy to electricity. The electricity can then either be directly used, or stored in batteries or some other storage means.
Problems exist in using wind power to turn turbines and windmills to generate electricity via generators. Wind strength depends on the difference in pressures. More specifically, wind on earth occurs due to the difference in temperatures between the equator and the poles, and the rotation of the planet. Because weather patterns may affect the difference of pressures, and thus, the strength of winds, the amount of rotation of the turbine and windmill blades will vary. In some instances, this variation could be great. One day may not have enough wind to turn the turbines at all, while the next may have too strong winds that cause the blades to rotate too fast, which could lead to damage to the devices. Problems exist in trying to deal with the varying strengths of wind.
In the past, people have used governors or differential drive units to try to control the rotational velocities of the turbines. The devices utilize a set of gears and an electrical switch for determining when the rotational velocity has become too great. Once the rotational velocity of the turbine blades are controlled, the switch is deactivated and the turbine runs as normal. However, this type of arrangement requires the use of several moving parts, and some needing electrical power of their own to operate. If any one of the parts fails or is damaged, the entire device must be shut down and rebuilt, which is costly and time consuming. In addition, devices only include ways to limit or slow down the rotational blade velocity, and do not include means to aid the turning of the turbines on days of low winds without using electricity themselves.
Newer turbines include complex computerized systems to control the rotational velocity of the turbine blades. During periods of high winds, most modern turbines contain a computerized shut-off switch to protect the long blades. The modern turbines require vast amounts of money to both build and maintain, however. Computerized systems are expensive to incorporate. If these systems fail or are damaged, the time, cost, and difficulty in replacing or fixing the computer systems may be more than the benefit derived from the wind turbine itself.
Therefore, the present invention addresses the problem of providing a speed controllable, electricity generating wind turbine which is cost-effective to maintain and that will be productive and efficient in a wide range of wind strengths.